The cardiac scintillation probe is a transportable device used to noninvasively monitor left ventricular function. The system uses nuclear medicine ECG-gated scintigraphic techniques and consists of a small detector and microcomputer system mounted on a cart. The cardiac scintillation probe, when used in conjunction with left ventricular (LV) catheterization, permits simultaneous quantification of the variation of LV volume and pressure allowing parameters such as LV compliance to be continuously monitored. In addition, measurements such as ejection fraction, filling and ejection rates, and temporal relationships can be made.